An ozone generating apparatus includes a ground electrode formed of a metal tube, an electrode having an electrically conductive layer formed on an inner surface of a cylindrical glass tube (dielectric body), and a high voltage electrode disposed on an inner diameter portion of the glass tube. An oxygen-containing gas is supplied to a gap between an inner side of the metal tube and an outer side of the glass tube. A high voltage is applied to the ground electrode and the high voltage electrode to generate an ozonized gas due to electric discharge (refer to Patent Document 1).